Automobile heater



March 21, 1950 H. HAIUSLADEN AUTOMOBILE HEATER Filed March 24, 1948 M /35 //3 //2 I //5 m3 #0 H m5 E 45 93 Q M7 H v 32 /05 FIG I A Q D D 47 fi M INVENTOR. HAROLD L. HAUSL ADEN ATTORNEY Patented Mar. 21, 1950 UNITED STATES PATENT OFFICE '7 Claims.

This invention relates to vehicle heaters and more particularly to vehicle heaters of the type adapted to warm the passenger compartment of a motor vehicle, such as an automobile and the like, by heating a portion of the fluid used in the cooling system of the engine of the vehicle and passing the heated fluid through a radiator positioned in heat exchange relation to the interior of the passenger compartment.

Automobile heaters having a radiator positioned in heat exchange relation to the passenger compartment of an automobile are, perse, relatively old in the art. However, in the past, the majority of such automobile heaters have been of the type commonly referred to as hot-water heaters wherein the coolant fluid of the vehicle engine was passed through the heater radiator, the temperature 'of the fluid passing through the heater radiator depending on the temperature to which the fluid in the cooling system was heated by the operation of the vehicle engine. Such heaters have had several inherent disadvantages, one of these disadvantages being that the heaters were slow-acting after the engine was first started, it being necessary for the fluid in the entire cooling system to warm to substantially normal operating temperature before any appreciable amount of heat was derived from the heater. Another disadvantage of such heaters has been that, because the effectiveness of the heater was dependent on the temperature of the fluid in'the cooling system of the vehicle, in order to insure sufficient heat being supplied to the heater for passenger comfort it has been necessary to maintainthe temperature of the coolant fluid in the engine at relatively high levels by various means such as, for example, by using thermostats in the cooling system, this practice, in many instances, resulting in maintaining the temperature of the coolant at a level above the preferred temperature for ideal engine operations.

A primary object of my invention is to overcome the aforementioned, and other, disadvantages of the hot-water heaters by providing a novel heater which, although it uses fluid from the cooling system of the vehicle in which it is embodied to afford the Working fluid or heat transferring medium, heats the working fluid independently of the cooling system of the vehicle.

Another object of my invention is to enable a novel vehicle heater, of the type adapted to use fluid from the. cooling system of the engine of the vehicle as'the heat-transfer medium, to be constructed which is efiective .to efflciently'provide heat for the passenger'compartment f. the

ine of the vehicle and irrespective of whether the temperature of the fluid in the engine-c001 ing system of the vehicle is high or low.

In my novel heater, a heat exchange unit is mounted in heat exchange relation to a portion of the exhaust duct, such as, for example, the exhaust manifold, of the engine of the vehicle to be heated and the working fluid used in the heater is passed through the heat exchange unit and is heated by the hot products of combustion which pass through the exhaust duct during normal operation of the engine and are effective to heat the exhaust duct to a relatively high temperature. Heaters of this general nature have been heretofore known in the art. However, such heaters heretofore known have had several inherent disadvantages such as, for example: being so constructed that they interfered with the flow of combustion products through the exhaust system of the engine of the vehicle being heated; requiring special pumps and the like for feeding fluid through the heater; requiring special auxiliary supplies of fluid; or, being complicated in construction, inefiicient in operation and expensive to manufacture.

.It is an object of my invention to enable a vehicle heater of the type which utilizes fluid taken from the cooling system of the vehicle engine and heated by the exhaust gases of the engine, to be constructed, and to operate in a novel and expeditious manner.

Another object of my invention is to enable a vehicle heater of the aforementioned type to be constructed which is relatively simple in con struction, may be economically produced commercially and may be readily installed in a motor vehicle.

A further object of my invention is to so construct a vehicle heater of the aforementioned type that the working parts thereof may be relatively easily removed and replaced.

Yet another object of my invention is to construct a vehicle heater of the aforesaid type in a novel and expeditious manner whereby, during the operation thereof, it is enabled to produce a relatively large amount of heat.

Another object of my invention is to construct a vehicle heater of the aforementioned type wherein the flow of fluid therethrough is controlled in a novel and expeditious manner in accordancewith the pressure and fluid level therein.

A further object of my invention is to so construct a novel heater of the aforementioned typewhich is effectively protected against dangerously high internal pressures and dangerously low internal pressures.

Another object of my invention is to provide a novel heater wherein working fluid is prevented from circulating therethrough until the temperature of the working fluid is sufiiciently high to afford a good heat-transferring medium.

Another object of my invention is to construct a novel vehicle heater of the. aforementioned type which; although using fluid from the cooling system of the engine of the vehicle to provide the working fluid of the heater, operates in a manner whereby the temperature of the main body of the coolant fluid in the cooling system is not raised appreciably and whereby the normal operation of the heater doesnot cause boiling of! of the coolant fluid from the cooling system.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawing which, by way of illustration, shows a preferred embodiment and the principles thereof and what I. now consider to be the best mode in which I have contemplated applying those principles. Other embodiments of the invention embodying the same, or equivalent principles may be used and structural changes may be made. as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

Fig. 1 is a side elevational view of the heater embodying the principles of my invention and and showing the heater in installed. position in a motor vehicle, certain of the partsthereof being shown diagrammatically;

Fig. 2 is an enlarged detail sectional view of a portion of the heater shown in Fig. 1;

Fig. 3 is an enlarged detail sectional view of another portion of the heater shown in Fig.

Fig. 4 is a sectional view taken substantially on the line 44 in Fig. 2;

Fig. 5 is a sectional view taken substantially on the line 5-5 in Fig. 2;

Fig. 6 is a sectional view taken substantially on the line 66 in Fig. 2; and

Fig. 7 is a detail sectional View taken substantially on the line 1---[ in Fig. 2.

In the drawing, a heater Ill is shown to illustrate a preferred embodiment of my invention. The heater H3 comprises, in general, a heat-exchange unit or boiler B' mounted on the exhaust manifold M of the engine E of a motor vehicle and having one end connected to the radiator R. of the vehicle to receive coolant fluid therefrom. The other end of the boiler B is connected to one end of another heat exchange unit or radiator I-I mounted in the passenger compartment P of the motor vehicle, the other end of the radiator H being connected by a return connection to the radiator R.

- Both the inlet connection of the boiler B to the radiator R and the return connection of the heater-radiator H to the radiator R are made through a control unit C which is operable in a novel and expeditious manner to control the circulation of working fluid through the heater 10. During the operation of my novel heater ID, as will be discussed in greater detail presently, coolant fluid flows from the radiator R into the boiler B where it is heated and passes into the radiator H to afford heat for the passenger compartment P.

The control unit 0 through which the boiler B is connected to the radiator R, includes a substantially T-shaped fitting l2. A manually operated shut-off valve or control valve I4 is connected to one arm of the fitting l2 by suitable means such as a collar I6, and a return valve I8 is similarly connected to the opposite arm of the fitting l2 by a collar 20.

An inlet valve 22 having a housing 24 is connected at one end to the control valve 14 by a collar 26 and is connected at the other end by a coupling member 28 to one end of the boiler B.

' Thus, it will be seen that the fitting I2, return valve l8, control valve 14 and inlet valve 22 form an integral unit comprising the control unit 0.

The inlet 30 of the fitting 12 is connected by a suitable conduit. such as a tube 32 to the lower end of the vehicle radiator R, this connection preferably being made on the pressure side of the water-pump in those vehicles employing water-pumps in their cooling systems. The tube 32 affords an inlet conduit through which coolant fluid from the. radiator B may flow into the fitting i2, and, because the fluid level in the radiator R is above that in the fitting 12, the fluid thus fed to the fittingi2 is under a slight pressure irrespective of whether or not the vehicle in which my heater is embodied employs a water-pump.

The shut-off valve l4 comprises the usual type of two-way valve having a housing 34 through which a passageway 36 extends. A plug member 38 extends transversely through the passageway 36 and is retained in. the housing 34 by suitable means such as a pin 40- and a snap-ring M. The plug member 38 is rotatably mounted in the housing 34 and has a slot 43 extending therethrough which, when the plug member 38- is positioned as shown in Fig. 2, affords a passageway through which fluid may flow from one end of the valve to the other. When the plug member 38 is rotated in the housing 34 to a position at right angles to that shown in Fig. 2, the slot 43 is moved out of communication with the end portions of the passageway 36 to thereby close the valve M. Manual control of the valve 44 is afforded by a shaft or cable 45 having one end connected to the plug member 38 and the other end extending into the passenger compartment P of the vehicle and having a handle 41 mounted thereon, whereby the occupant of the passenger compartment by manipulating the handle 41 may adjust the setting of the valve 14. The housing 24 of the inlet valve 22 has a nipple 5U projecting therefrom which afiords the connecting member to which the collar 26 is attached, suitable threads 51' being formed on the outer surface of the nipple 5B for this purpose. A circular shaped valve seat 53, having a central opening 55 formed therein, Fig. 2, is mounted in the nipple 50 and. aflords a seat for a valve member 51. The valve member 5'!- comprises an elongated shaft 59' having a substantially triangular shaped head 6|).- formed thereon. The lobes. 62, 63 and 64, Fig. 4, of the valve head 60 engage the inner wall of the nipple 50 and afford guide members for valve member 51.

The valve stem 59 extends through a boss 68 formed on one end of an arm '68, the other end [0 of the arm- 68 being attached to the. center portion of a diaphragm 12 mounted in one wall 14 of the housing 24. The end of the valve stem 59 opposite the end to which the valve head 60 is attached, is engaged with one arm 18 of a bell crank lever 18, the bell crank lever 18 being pivotally mounted in the housing 24 by a pin 19 projecting inwardly from one wall of the housing 24. The other arm -8I of the bell crank lever 18 is connected to a float 83 mounted in the housing 24 for a purpose which will be explained in greater detail hereinafter.

A bracket arm 85 extends outwardly from the housing 24 of the inlet-valve 22 and has one end extending over the central portion of the diaphragm 12. A bolt 81 extends through a tapped opening formed in the free end of the arm 85 and is operable to be moved toward and away from the diaphragm 12. A compression spring 89 is mounted between the arm 85and the diaphragm 12 with one end engaged with the end In of the arm 68 and the other end mounted in a cap member 9I engaged by the bolt -81. The bolt 81 affords effective means for adjusting the compression of the spring 89 and thereby aflz'ords means for readily adjusting the inward force of the spring 89 on the diaphragm 12.

The boiler B comprises a tube 93, formed of any suitable material such as copper, which is mounted on, and extends along, the manifold M of the engine E. A sheet of suitable insulating material, such as asbestos, is mounted on the tube 93 and the manifold M to form a cover 95 therefor. Three bands 91, 98 and 99, formed of a suitable material such as steel, are mounted on the cover 95 and are effective to hold the tube 93 in tight contact with the manifold M to thereby insure good heat exchange relationship therebetween.

The end of the tube 33 opposite that to which the inlet valve 22 is attached is connected by a suitable coupling member Illl to the inlet of the heater-radiator H. The radiator H may be of the conventional automobile-heater type and is mounted in the passenger compartment P by a suitable bracket :I03 attached to the front wall of the compartment. A blower unit I05 comprising the conventional fan I01 and motor I08 is mounted between the radiator H and the front wall of the compartment P and is adapted to blow air across and through the tubes of the radiator H during the operation of th heater I0. Suitable controls such as a manually operable switch III] and a thermostatically controlled switch II2, responsive to the temperature of the air in the passenger compartment P and having a control button II3 for effecting manual adjustment, ma be mounted in the passenger compartment P for controlling the operation of the motor I08 and thereby controlling the operation of the blower I05.

The outlet end of the radiator H is connected by a suitable conduit or tube I I5 to the inlet end of the return-valve I 8. The return valve I8 comprises an elongated housing I I6 having a pamageway II'B extending therethrough. A valve seat I20, Fig. 2, similar to the valve seat 53, and having a central opening I22 formed therein is mounted in the passageway I I8 and affords a seat for a valve member I24. The valve member I24 comprises a stem I26 having a head I21 mounted on one end thereof, the head I21, like the head 6B of the valve member 51, being substantially triangular in shape and having three lobes engageable with the interior of the housing H 8 to aiTord a guide for the valve member I24.

An annular-shaped spring-seat I29 having threads formed on the outer peripheral edge portion thereof is adjustably mounted in the passageway I I8, the threads on the outer surface of the spring-seat I29 being engaged with complementary threads I3I formed on the inner surface Of the housing II6. A compression coil spring I33 is mounted between the valve head I21 and 6 the spring seat I29 and isnormally efl'ective to yieldingly hold the valve member I24 in engagement with the valve seat I20 to thereby close the valve I8. Thus it will be seen that the valve I8 affords an effective one-way valve which is operable to automatically prevent the flow of fluid therethrough from the tube 32 to the tube II5, but is. operable to automatically open, when the pressure in the tube I I5 becomes high enough to overcome the spring I33 and force the valve member I24 downwardly away from the valve seat I20,

to thereby permit the return flow of fluid from the tube II5 into the tube 32 and then into the cooling system of the engine E.

Another one-way valve I35, which may beidentical to the return valve IS in the control unit C, is mounted onEthe conduit II5 connected between the radiator H and the return valve I 8. This valve I35 is mounted on the conduit I I 5 with the outlet side thereof connected to the conduit II 5 and the inlet side in communication with the atmosphere. Thus it will be seen that when the pressure in the conduit I I5 is equal to, or greater than, the atmospheric pressure the valve I35 will be closed to thereby prevent the How of fluid therethrough. However, it will also be seen that if the pressure in the conduit I I 5 drops below atmospheric pressure a predetermined amount, as determined by the adjustment of the spring in the valve I35, the valve I35 will be caused to open and permit air to pass into the conduit I I5 to thereby prevent the pressure in the tube I I5 from dropping to a sufficiently low level that the tube, or other parts of the heater I 0, are caused to collapse.

It has been found that when it is desired to shut off my novel heater, closing of the valve I4 and opening of the switch IIII, thereby shutting, off the supply of fluid from the radiator R to the boiler B and stopping the blower unit I05, is effective to do so in a practical manner.

Operation At the initiation of a typical operation of my novel heater, when the passengers first enter the compartment P of the vehicle in which the heater is installed, the valve I4 will normally be closed so that little or no coolant fluid will be present in the boiler B, and the engine E and, therefore, the boiler B will be cold so that the pressure in the housing 24 will not be suflicient to flex the diaphragm 12 outwardly. Thus, the valve 51 will normally be open at this time.

After the passengers are in the compartment P, the engine E is normally started and thehandle 41 then turned to open the valve I4.

Coolant fluid may then flow from the radiator R through the conduit 32, the fitting I2,'the control valve I 4, and the valve seat 53 into the housing 24 and the boiler tube 93. As the level of the fluid rises in the housing 24 and the boiler B, the float 83 is raised thereby and causes the bell-crank 18 to pivot on the pin 19 in a clockwise direction, as viewed in Fig. 2. Rotation of the bell-crank in a clockwise direction causes the arm 16 to swing upwardly to thereby move the valve member 51 toward the valve seat 53. When the fluid level in the boiler B and the housing 24 has raised to a predetermined level the float 83 and bell crank 18 are effective to seat the valve 51 on the seat 53 and thereby close the nipple 50 against further flow of fluid therethrough into the housing 24.

The level of the fluid in the boiler tube 93 when the valve 51 is closed by the float 83, is

preferably such that a relatively thin layer of fluid is present in the boiler B so that the fluid in the boiler B may be quickly and easily heated and also so that ample space is insured for the relatively free passage of vapor through the tube 93. Thus, for example, it is desirable, when using a tube 93 having an inside diameter of one-half an inch, to so construct and arrange the control unit C that the float 83 will cause the valve 5? to close when the tube 93 is approximately half full.

Theexhaust manifold M of the customary engine E is heated by the exhaust gases passing therethrough to a relatively high temperature within a short time after starting of the engine. Aspreviously stated, the tube 83 is maintained in good heat-exchange relationship with the manifold M by the bands 91, 98 and 99 and is protected from the cooling effects of the outside. atmosphere by the insulating cover 95 so that it too is relatively quickly heated and is effective to cause vaporization of fluid in'the boiler B within a relatively short time after the engine E is started.

The vapor or steam generated in the boiler B is prevented from flowing back through the housing 24 into the radiator R by the inlet valve 51 whichis eflective as a one-way valve. As a result, the vapor pressure increases in the boiler B and the housing 24 and causes vapor to flow through the tube I9! into the heater-radiator H to thereby heat the latter. After the radiator H-has been warmed the switch I I may be manually closed to thereby energize the motor I98 and drive the fan II)? to blow air across and through the radiator into the passenger compartment P in the usual manner. This flow of air across and through the radiator H, of course, causes the air to be heated and thereby heats the passenger compartment P of the vehicle. In addition, the loss of heat from the vapor in the radiator H to the air circulating around the latter normally causes condensation of a substantial portion of the vapor in the radiator H, which condensate flows back through the tube ill! into the boiler B where it is reheated and again vaporized.

During initial operation of the heater ID, the pressure in the boiler B and the housing 24 does not become high enough to flex the diaphragm T2 outwardly sufflciently to cause the arm 68 to actuate the valve 5'! and, therefore, the opening and closing of the valve 51 is controlled by the float 83, the float 8'3 dropping and permitting the valve 51 to open and thereby permit more fluid to flow into the boiler B when the fluid level in the boiler B drops below the aforementioned predetermined level, and the float 83 raising to thereby positively close the valve 51 when the fluid level in the boiler is at or above the aforesaid predetermined level. However, after normal operation of the heater Ill is attained, the pressure in the boiler B and the housing 24 increases above a predetermined pressure, as determined by the adjustment of the spring 89, and the diaphragm 12 is flexed outwardly thereby and causes the boss 66 on the arm 38 to move into engagement with the head 6!] on the valve member 51 to thereby positively hold the valve '51 in closing engagement with the seat 53 to prevent the further flow of fluid into the housing 24 and the boiler B while this highpressure condition prevails. The spring I33 in the return valve '18 is so adjusted that it is effective to hold the valve I24 in closed position against the pressure normally developed in the heater I0. Thus it will be seen that after normal operation of my novel heater is attained it comprises a substantially closed unit, the amount of fluid therein and the amount of heat being applied thereto being in such balance that substantially a state of equilibrium exists, the pressure in the heater I 0 being suflicient to cause the diaphragm T2 to maintain the inlet valve 5'! in closed position but being insufficient to cause the return valve Hi to open. When this state of equilibrium exists it will be seen that a relatively great amount of heat is supplied tothe heater radiator H, the vapor being heated to a relatively high temperature.

If during operation of my novel heater, the pressure therein becomes greater than a predetermined amount, as determined by the ad- ,justmentof the spring H3 in the return valve I8, the valve member I24 is moved thereby 'into open position relative to the valve seat I20 to thereby relieve the pressure therein by permitting return flow of fluid from the tube H5 of the heater l0 into the radiator R of the vehicle cooling system. This return flow of fluid into the cooling system of the vehicle is so slight during normal operation of my heater that it is readily absorbed by the larger mass of fluid in the cooling system without loss in the form of vapor and without raising the temperature of the coolant to any appreciable extent.

,The spring 88 controlling the movement of the diaphragm I2, and the spring 133 of the return valve I8 are so adjusted that the relative strengths thereof are such that the valve 57 will be closed by the arm 68 at a lower pressure in the heater I0 than the pressure at which the valve I8 will open.

If during the operation of the heater Ill, the pressure falls below the pressure required to distend the diaphragm to valve closing position, the arm 66 moves inwardly away from the valve head 60 and thereby frees the valve 51 to the control of the float 83 so that the valve 57 will again .be opened and closed in accordance with the "fluid level .in the boiler 13 and housing H as previously discussed.

Thus it will 'be'seen that the diaphragm 12, th float 83, the valve 51 and the return valve I24 cooperate with each other in maintaining the proper pressure and fluid level in the heater I0.

In some instances, such as, for example, after the heater ID has been operated at high heat output, during which a relatively large amount of fluid and vapor is present therein, if the engine E were shut off and allowed to cool the vapor present in the heater I0 would be caused to-condense, thereby creating a partial vacuum therein. In some instances, if this vacuum were uncontrolled the difierence in pressure between the interior of the heater I0 and the outside atmosphere might be sufiicient to cause collapse or other serious damage to the radiator H, the boiler B or other parts of the heater Ill. However, with the valve I35 embodied in my novel heater, this danger is eliminated, the valve I35 being operable to open when the pressure in the heater I0 decreases below a predetermined pressure and thereby vent the heater to the atmosphere.

From the foregoing it will be seen that Ihave provided a novel vehicleheater which is quickly operable after the engine of the vehicle to be heated is started. Also, it will be .seen that although my heater utilizes the waste heat of the'exhaust gases to heat working fluid, comprising a portion of the coolant'fluid of theengine of the vehicle, to a relatively high temperature, this is accomplished in a novel and expeditious manner whereby no interference is caused to the flow of exhaust gases and also whereby no appreciable loss of coolant fluid from the cooling systemresults.

Furthermore, it will be seen that the operation of my novel heater during a heating operation is effectively controlled by cooperating pressure sensitive and fluid-level sensitive means which are constructed and operate in a novel and expeditious manner. In addition it will be seen that I have provided a novel heater which is eflicient in operation; may be readily and economically produced commercially; may be quickly and easily installed in a motor vehicle; and wherein the working 'parts maybe quickly and easily removed and replaced if it is desired to do so. I Hence, while I have illustrated and described the preferred embodiment of my invention, it is to be understood that this is capable of variation and modification and'I, therefore, do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim: 1. An automobileheater 'for use in an automobile having an internal combustion engine including an exhaust duct for discharging products of combustion and a cooling system using fluid as a cooling means, said heater comprising a heat exchange unit adapted to be mounted in heat exchange relationship onsuch an exhaust duct, conduit means adapted to be connected to such a cooling system and said heatexchange unit for feedingsuch fluid from said cooling system to said heat exchange unit to aflord working fluid for said heater, valve means for controlling the flow of said fluid through said conduit means into said heat exchange unit in accordance with the quantity of fluid present in said heat exchange unit, said valve means being adapted to automatically close: to thereby prevent the passage of fluid through said conduit means into said heat exchange means when the quantity of fluid in said heat exchange means is more than a predetermined quantity, a radiator adapted to be mounted in operative position in said automobile, means for feeding working fluid from said heat exchange'unit into said radiator, and means for feeding working fluid from said radiator to'said 55 cooling system.

2. An automobile heater for use in an automobile having an internal combustion engine including an exhaust duct for discharging products of combustion and a cooling system using fluid as the cooling means, said heater comprising a heat exchange unit adapted to be mounted on said engine in heat exchange relationship with such an exhaust duct, conduit means for feeding such fluid from such a cooling system to said heat exchange unit, a valve connected to said conduit means and operable to be opened and closed to thereby control the flow of fluid through said conduit means into said heat exchange unit and thereby control the pressure in said heat exchange unit, control means connected to said valve and effective to control the opening and closing of the latter, said control means including a float responsive to the level of fluid in said heat expressure in said heat exchange unit, a radiator,- conduit means for feeding working fluid from said heat exchange unit into said radiator, and

conduit means for feeding working fluid from said such fluid from 'said' cooling system intosaid heat exchange unit,- a second elongated duct adapted to beconnected between said radiator and said-cooling systemiforfeeding working fluid from said radiator to said coolingsystem, a valve in said first mentioned, elongated ductand operable to be opened and closed to thereby control the flow of fiuidthrough the latter into said heat exchange'unit, means operable by the fluid in said heat exchange unit forcontrolling the openingand closing of said valve, and a second valve in.

said second elongated duct and operable to be opened and closed to thereby control the flow'of working-fluid from said radiator through said second duct into said cooling system, said second,

valve being responsive to pressurein said second duct and being adapted to open when the pressure in said secondductis above 'a predetermined pressure and being adapted toclose when the pressure in said second duct is below said pre: determined pressure.

4. An automobile'heater for use in an automo-: bile having an internal combustion engine including an exhaust duct for discharging'products of combustion and a cooling system using fluid as the cooling means, said heater comprising a heat exchange unit adapted to be mounted on said exhaust duct in heat exchange relation thereto, an elongated duct adapted to be operatively connected between such a cooling system and said heat exchange unit for feeding such fluid from said cooling system into said heat exchange unit to afford working fluid for said heater, a radiator connected to said heat exchange unit for ing fluid from said radiator to said coolin system, a valve in said first mentioned elongated duct and operable to be opened and closed to thereby control the flow of fluid through the latter into said heat exchange unit, means operable by the fluid in said heat exchange unit for controlling the opening and closing of said valve, and a second valve in said second elongated duct and operable to be opened and closed to thereby control the flow of working fluid from said radiator through said second duct into said coolin system, said second valve being responsive to pressure in said second duct and being adapted to open when the pressure in said second duct is above a predetermined pressure and being adapted to close when the pressure in said second duct is below said predetermined pressure, and means for automatically venting said second duct to the atmosphere when the pressure in said second duct is below a predetermined pressure.

5. An automobile heater for use on an autochange unit and a diaphragm responsive to the 76 mobile of the type having a fluid-cooled inter- 11 no.1 combustion engine, said heater comprising a boiler adapted to be mounted in heat exchange relation on an exhaust ductof such engine for receiving heat from said exhaust duct during op eration of said engine, means including insulating material for holding said boiler in such position relative to said exhaust duct, an inlet conduit adapted to be connected to said boiler and to the cooling system of said engine for feeding such fluid from said engine into said boiler, said boiler being effective to heat said fluid f-ed therein'to during normal operation of said engine, a heat exchange unit adapted to be mounted in heat exchange relationship "with the interior of the passenger compartment of automobile, conduit means for feeding fluid from said :boiler into said heat exchange unit for 'heatmg the latter, an outlet conduit adapted to be connected between said heat exchange unit and said cooling system {or ieeding fluid from said heat exchange unit into said cooling system, valve means mounted in said inlet conduit and responsive to the level of fluid and to the pressure in said boiler for controllin the flow of fluid through said inlet conduit into said boiler, said valve means being responsive to fluid levels above a predetermined level in said boiler and to pressures above a predetermined pressure in said :boiler to close said intake con,

duit and thereby prevent the passage of fluid through said intake conduit from Said cooling system to said boiler, and a check valve operatively mounted in said outlet conduit, said check valve being operable to permit the passage of fluid through said outlet conduit from said heat exchange unit to said cooling system and to prevent the reverse flow therethrough.

6. An automobile heater for use on an automobile of the type powered by an internal combustion engine having a cooling system using fluid as the cooling means, said heater comprising an elongated tube adapted to be mounted on the exhaust manifold of such an engine in heat exchange relation therewith, means for holding said tube in said relation to said manifold, an inlet conduit adapted to be connected to said tube and to such a cooling system of said engine (for feeding fluid from said cooling system into said tube, said tube being efiective to heat said liquid fled thereinto during normal operation of said engine, said conduit including a control unit for controlling the flow of fluid therethrough into said tube, said control unit comprising a one-way valve operable to be opened and closed to thereby open and close said conduit, and means responsive to the fluid level and pressure in said tube for controlling the opening and closing of said valve, :a radiator adapted to be mounted in the passenger compartment of such an automobile in heat exchange relationship with the interior thereof, means for feeding fluid drom said tube into said radiator, and means for feeding fluid from said radiator into said cooling system of said engine.

7. In an automobile including a passenger compartment, an internal combustion engine having a cooling system using fluid as the cooling means, and an exhaust duct for discharging hot combustion products from said engine, a

radiator mounted in said compartment in heat exchange relation with the interior thereof, means including :a boiler for feeding hot "working fluid to said radiator, said boiler being mounted on said exhaust duct heat exchange relation therewith :for heating by such combustion products during an operation of said engine, conduit means connected to said cooling system and said boiler for feeding such fiuid from said cooling system to said boiler, other conduit means connected to said radiator and said cooling system for feeding working fluid from said radiator to said cooling system, valve means for venting said other conduit means to atmosphere when the pressure therein is below a predetermined pressure, said valve means being operative to close when the pressure in said other conduit means is above said predetermined pressure, and means for controlling the flow of working fluid through said radiator, said last named means comprising valves mounted in said first mentioned conduit means and said other conduit means and responsive to pressure therein to effect opening and closing of said first mentioned and said other conduit means, said valve in said first mentioned conduit means being responsive to the fluid level in said boiler and being effective when the fluid level therein is above a predetermined level to close said first mentioned conduit means.

HAROLD iL. HAUSLADEN.

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